A severe combined immunodeficiency (hereinafter, referred to as “SCID”) occurs in humans (Buckley, R. H. Annual review of immunology 22, 625-655 (2004)). However, a medicine for treating the SCID is as yet undeveloped due to the limited animal model reflecting a human SCID type. A pig has physiological properties that are very similar to those of humans and a higher similarity as compared with rodent models, which has been designed to copy many human diseases (Whyte, J. J. & Prather, R. S. Molecular reproduction and development 78, 879-891(2011)). Therefore, a SCID pig may be representative of the models that have been designed to copy human diseases. In addition, the SCID models may be used for a cancer research, cell transplantation, and drug development study.
A recombination activating gene 2 (hereinafter, referred to as “RAG2”) is involved in the autosomal-related SCID diseases in humans (Villa, A., Santagata, S., Bozzi, F., Imberti, L. & Notarangelo, L. D. Journal of clinical immunology 19, 87-97 (1999)). A mutation in the RAG2 causes damaged B and T cells, and since the RAG2 is important for V(D)J rearrangement, it destroys an adaptive immune system (Shinkai, Y. et al. Cell 68, 855-867 (1992)).